Catalysts for polymerization of olefins



minum dichloride, methyl aluminum dichloride, dimethyl aluminum chloride, or trimethyl aluminum in an inert solvent like n-heptane at -40 C. to above room temperature. Pressures above atmospheric pressure may be used particularly to maintain a liquid phase if low boiling hydrocarbon diluents are used. Of course, this embodiment of the inventiond may be applied not only to the restoration of polymerization activity but also to the enhancing of the catalytic activity of active but weakened catalysts by the addition of solutions of the alkyl aluminum compounds mentioned to the catalyst mixtures obtained from titanium tetrachloride and triethyl aluminum or diethyl aluminum chloride, or the like before they have lost their activity. Y

In accordance with another embodiment of this invention, stable catalyst stock may be prepared which may be used in batch or continuous polymerization of ethylene and other oletins. The brown solid which is obtained from titanium tetrachloride or its equivalent and triethyl aluminum or diethyl aluminum chloride or their equivalents as described above is separated preferably by tiltration in an inert atmosphere. The mother liquor is removed by washing with an inert solvent, preferably a saturated hydrocarbon, the solid is reslurried in an inert solvent like n-heptane, and stored in the absence of moisture, oxygen and other reactive gases. This mixture is linactive or only slightly active for the polymerization of olens The activity depends somewhat on how well it was washed and how long it was stored before and after it was filtered, as well as whether it was prepared from triethyl aluminum or diethyl aluminum chloride.t This brown solid may be stored in the inert solvent indefinitely without affecting its utility for this embodiment of the invention. When needed as catalyst for oleiin polymerization, this stable slurry of brown solid is added to the polymerization vesselwith the addition of a solution of methyl or ethyl aluminum dichloride, -dimethyl aluminum chloride, trimethyl aluminum or Vother alkyl aluminum compound. The resulting mixture' is active as a catalyst for the polymerization of ethyleneand otheroletins.

For a batch polymerization the stable slurry of brown solid may be added tirst and all or part of the activating alkyl aluminum compound is added just before orduring the introduction of the olefin. 'The solution of activating alkyl aluminum compound may also be added during the polymerization until no more polymerization takes place. For a continuous process the stable slurry of brown solid may be premixed with the activating alkyl aluminum compound or the two components may be added with the aid of diluents in separate streams simultaneously to the polymerization vessel.

As previously mentioned, for an optimum catalyst mixture from titanium tetrachloride or its equivalents and alkyl alum-inum compounds, it is necessary carefully to control the temperature and time of contact of these ingredients after they are mixed and prior to the polymerization of ethylene. The detrimental eiects of undesirable variations in these conditions may be greatly minimized by the present invention. For this purpose only part of the aluminum compound is mixed with the titanium tetrachloride or equivalent and this -is allowed to react to give the maximum yield of brown solid, i.e. maximum reduction. Higher temperatures and Ylonger times than heretofore can be used without detrimental end etfects and the mixture may be stored longer. This slurry may be treated in accordance with the invention or the brown solid may be separated and mixed with an inert solvent like n-heptane before it is added to the polymet-ization vessel. The separated solid is more stable on storage if it is filtered and stored in the inert solvent. At the time of polymerization, the remaining or additional amount of alkyl aluminum compound is added to obtain an active catalyst. The alkyl aluminum compound added at the time of polymerization may either be the same as or different from that originally used. More particularly, alkyl aluminum compounds of lower reducing activity than those originally used may be employed at this stage, for example, ethyl or methyl aluminum dichloride, dimethyl aluminum chloride, trimethyl aluminum, etc.

This embodiment of the invention provides a much more flexible and easily controlled method of catalyst preparation, as well as a more active catalyst system, than when all of the aluminum compound is mixed at once with the titanium tetrachloride. It is also interesting to note that there is no advantage in adding originally only part of the titanium tetrachloride to the triethyl aluminum or diethyl aluminum chloride. Furthermore, operation in accordance with the present invention leads to substantially increased molecular weights of the product polymer.

In all embodiments of the invention the polymerization may be run batchwise by feeding the inactivated catalyst slurry containing the brown solid to the polymerization vessel and adding all or part of the solution of activating alkyl aluminum compound to the vessel just before or during the introduction of the olefin, such as ethylene. A solution of activating alkyl aluminum compound may also be added during the polymerization until no more polymerization takes place.

The polymerization may also be carried out as a continuous process. In this case, the unreactivated catalyst mixture containing the brown solid and the solution of activating alkyl aluminum compound may beA premixed before addition to the polymerization vessel or they may be added as separate streams. There is no detrimental effect connected with adding separate streams in accordance with the present invention as it is known to be the case when a solution of titanium tetrachloride and a solution of triethyl aluminum or diethyl aluminum chloride are added separately to the polymerization reactor as the original catalyst ingredients.

In all other respects, catalyst composition and preparation as well as polymerization conditions may be those heretofore .used in the specific art of low pressureolen polymerization. Thus, a list of reducing catalyst components of outstanding utility includes the `following aluminum compounds: tri-n-octyl aluminum, tri-isobutyl aluminum, tripropyl aluminum and triethyl aluminum, and dialkyl aluminum halides, such as diethyl aluminum halides. Suitable aluminum compounds of somewhat lower reducing activity which are also useful as activating agents in accordance with the present invention nclude the following: dimethyl aluminum halides, trimethyl aluminum, methyl and ethyl aluminum dihalides, higher dialkyl aluminum halides and trialkyl aluminum compounds having alkyl groups higher than about Cm. Mixtures of aluminum alkyls can also be used. For example, mixtures containing ethyl aluminum dichloride and diethyl aluminum chloride have been successfully used to produce active catalysts in this manner. Similarly, mixtures of ethyl aluminum dichloride and triethyl aluminum or of diethyl aluminum chloride and triethyl aluminum can be used. All these compounds as well as methods for their preparation are well known in the art. Quite generally, in addition to trialkyl or aryl aluminum compounds, organo-aluminum compounds carrying two hydrocarbon radicals or at least one hydrocarbon radical and one hydrogen, as well as an electron attracting group, such as an alkoxy, halogen, organic nitrogen or sulfur radical, etc., may be used.

Other suitable reducing materials which may he used to prepare the unreactivated catalyst composite include the alkali and alkaline earth metals, their alloys, hydrides and their alkyl and/or aryl compounds, as well as quite generally the alkyl and aryl derivatives of other metals which have sufficient stability to permit reaction in their compound form with a reducible heavy metal compound,

1 purposes.

y Heavy metal compounds suitable for theV purposes of the invention include such inorganic compounds as the halides, oxy-halides, complex halides, oxides, hydroXides, androrganic compounds such as alcoholates, 'acetates, benzoates and acetyl acetonates of the transition metals of the IV, V, VI and V-ll periods of the periodic system, eg. titanium, zirconium, hafnium, thorium, uranium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and manganese, as well as iron and copper. The metal halides, particularly the chlorides, are generally preferred, titanium 'and zirconium being the most active of these metals. The following heavy metal compounds are relatively readily reducible Atitanium tetrabromide, titanium tetrachloride and zirconiumacetylacetonate. The relatively dilicultly reducible compounds include ferrous chloride, chromic chloride yand manganese chloride.

Particularly striking results have been obtained by applying the present invention to ethylene polymerization carried out with catalysts' prepared by reacting triethyl aluminum, diethyl aluminum chloride or mixtures of di-r ethyl aluminum Achloride With triethyl aluminum as the reducing agent with titanium tetrachloride as the heavy metal component.

The. original catalyst composites are quite generally prepared by intimately mixing the aluminum compound or other reducing component and the heavy metal compound preferably in a solvent or diluent andV in a non-` oxidizing atmosphere while stirring. Parafnic hydro-V carbons, such as heptane or`other saturated petroleum or synthetic. hydrocarbon oils, are the most suitablevsolvents. for this purpose as well as for the application' of the activating compounds of the invention.

The molar ratio of the aluminum compound to the heavy metal compound in the original as well as the activated fin-al catalyst mixture may vary widely. 'In general, the higher the polymer molecular weight desired the higher shouldv be4 this ratio. A preferred Vmolar ratio for alkyl aluminum compouuds'toV titanium vtetraclrloride for making polymers aboveY 20,000 molecular weight is about 1-1211, molar ratios of l-6:1 and even substantially equimolar proportions, based on metal, being suitable in many cases.

The; polymerization process employing the catalysts v prepared in accordancey with the invention is carriedgout at conditionsnormally used heretofore in the low pres- Y sureA polymerizationof oleiins to prepare'high molecular weight polymers suitable as plastics and for similar These conditions depend somewhat 'on the specific olefin involved and on vthe type of polymer de-r sired. Ethylene is the preferred olen: although higher oleiins, such as propylene, butylenes, styrene, hexadecene, butadiene, etc., may beused alone or in mixtures. The polymers produced have molecular weights abo/ve, 2000 and may range as high` as from 300,000-3,000.,000 and more as determined by the intrinsic viscosity method using the I'. Harris correlation (I. Polymer Science, 8, 361 (1952)). In the case of ethylene, the polymerization is carried out by intimately contacting gaseous ethyl ene with .the catalyst of the invention, for example by bubbling the ethylene into a suspension of the catalyst in` an inert solvent or diluent. Neither the polymerization temperature nor the polymerization pressure is particularly critical, It is preferred, however, to 4operate at temperatures of about el50 C., such as 2590 C.

Pressures ranging anywhere; from atmospheric: or subatmospheric to 250 atmospheres have been used heretofore in the low pressure polymerization of ethylene4 and other olens on catalystsA of the'type improved. bythe present invention. Similar pressures mayV be'.- used` for the processof-the invention. -1 f The react-ion is preferably carried out: under lcareful exclusion of oxygen While, stirring in batch. or continuous operation. When operating; batchwi'se, .oleiin introduction is continued until the catalyst is exhausted and 5 clude aliphatic, hydroaromatic and aromatic hydrocarbons, such as pentane, hexane, higher paratlins, cyclo hexane, tetrahydronaphthalene, dec'ahydronaphthalene,

benzene, xylene, halogenated aromatic "hydrocarbons, e.g. monoor cli-chlorobenzenes vand mix'tures thereof. The polymer concentration in the reactionv mixture ma be about l040%. Y Y

The amount of catalyst used may vary within wide limits depending somewhat on the purity of the olen feed; Proportions 4of'as litt1e,as0.1'part by weight of catalyst per 1,000 parts byweight of olefin are sutlicient if they feed is pure. With olefin feedY streams containing about. 0.01% ofwater, oxygen, carbon dioxide or certain other oxygenated "compounds, catalyst proportions of about 0.55 wtf percent are usually adequate.

Upon completion of the polymerization reaction, the catalyst is completelyv deactivated, e.g. by the addition of an alcohol, such as isopropyl alcohol or vn-'butylalcohol lyst used. The reaction slurry may then he filtered, the lter cake reslurricd in .a catalyst solvent, suchlas dry, concentrated alcohol vat about 50 100 C. lfor 15-60 minutes, filtered again and the lter cake dried, preferably under reduced pressure. Ash residues in the polymer are reduced below about 0.05% by this procedure.

The polymers produced hy the present invention are at least equal in quality and, in many cases superior to, those produced by conventional low pressure polymerization processes. l ofthe invention will be best understood by reference' to the Afollowing yspecific examples.

Example I f Five Inl. of a 0.843 molar solution of titanium tetrachloride in n-heptane and, ll.l m1. of a 0.790 molar Iadded toa dropping funnel containing ml. of dry `n heptane. VMore dry nfheptane was added to make the total volume'up to 25.0` ml: Thisvery light yellow solution transferred to a Pyrex glass polymerization vessel.; being'protectediatalltimes'lwith an atmosphere .45 oiV dry nitrogen'. The stirred,"mixture was hleatedto 50 deposited: on the sides of. the vessel. Purified dry ethyl- 500 mlt/mimwith no absorption nor evidence of polymer formation at room temperature (25 `27 C.) for 30` minutes; then heated toy 80 C. [for 15` minutes, al-

' lowed toy cool to 29 C., and again heated to 80 C.

and held therefor' I5v minutes. The total time of introducing ethylene at S00 ml./minf. was 2 hrs. and 55 minutes after whichv 50 ml. of isopropanol was added to decompose the catalyst. A clear colorless solution resulted with no evidence of polymer.

This'` experiment shows `that ethylaluminum dichloride does not react with TiCl4 to form an active polymeriza tion-v catalyst.

In another experiment 5 ml. ofv a 0843fmolar solution-y of titanium tetr-achlorideinA n-heptane and01876 molarl solution ot'. ethyl compoundl (87% tiri'- ethyl aluminum- 13% diethyl. .aluminum bromide.)y in.

n-heptane. were added to f5.0 ml; ofdry n-heptane inria i* Y A` -brownpreciptate formed: irnrn'fedi ately.V More dry :n.-heptane wasimmediately-'addedkto f dropping funnel'.

make the tota-l volume,V ofY Ythe. mixture lupfto l yAfter-"standing forranY hour'at roomv temperature the ture wals iltered: ina nitrogen fatmosph'ere'iaThe brown solid wasjreslurried Vinv dry 1iheptane andr renitered twice. .The brownz'solidwas. then rleslrriedin1250 5 75 m1. of n-heptane and transferred/to the .Pyrex glass j in amounts of about 10-100 times the amount :of cata- Y This and other more specific aspects solution of ethyl aluminum dichlor'ide. in n-heptane were 50?: Crandzheld at this temperature-for 49 minutesrand vth'eneooled to 27 C, 'withuan rice bath. No precipitate was formed'. but a few droplets of viscous yellow oil v eney was introduced into theY stirred liquidv at a rate ofV ..7 polymerization vessel. Pure dry ethylene was bubbled into the stirred mixture at a rate of 500 nal/min. for 9 minutes during which time the temperature increased from 24.2-32.8, C. The ethylene ratio was increased to 1,000 ml./min. and the temperature reached a maximum of 40.0 and then decreased to 35.4 C. with a total ethylene absorption to this time (31 min.) of about 7,500 ml. of ethylene. At this time addition `Was commenced of a 250 ml. n-heptane solution containing 11.1 ml. of a 0.790 molar solution of ethyl Aaluminum dichloride. tain ethylene absorption rates between 500 and 1,000 ml./min. at 32, 49, 61 and 108 minutes from the start of adding ethylene. The reaction temperature was maintained between 55-60 C. by Cooling with' an ice bath when necessary. Finally, ethylene absorptionY rate decreased to less than 100 ml./min.V and the temperature dropped to 32.8 C. After a total reaction time of -229 minutes, the catalyst was decomposed byA adding 50ml. of isopropanol. `The white solid polymer was removed by ltration, washed with isopropanol and dried in vacuo at 70 C. The dry polymer weighed 104.2 grams. It softened at 135 C., melted between 200-210 C., and had an intrinsic viscosity of 3.93 cm.3102/g. corresponding to a molecular weight of about 235,000 by the Harris correlation (I. Poly. Science, 8, 361 (1952)) which is also used in all subsequent examples.

This experiment demonstrates that ethyl aluminum dichloride, while not an active catalyst component itself, may be used to activate the separated low activity catalyst precipitate prepared from TiCl4 and an active alkyl aluminum compound.

Example II Ten ml. of a 0.843 molar solution of titanium tetrachloride in n-heptane and 10 ml. of a 0.685 molar solution of dimethyl aluminum chloride in n-heptane were added to 100 ml. of dry n-heptane at room temperature C.) in an atmosphere of dry nitrogen. This mixture was diluted withrmore dry n-heptaneto bring the total volume up to 200ml. This mixture was prepared in a dropping funnel which could be transferred to the Pyrex glass` polymerization vessel without introducing air or moisture. A syrupy light yellow liquid settled to the bottom of the droppingfunnel but no solid was formed. The mixturewas addedgztothepolymerizaton vessel which contained 500 ml. of dry n-heptane. Puriand minutes, after which 50 mljof isopropanol was This wasv added in 50 ml. portions `to mainto 100 ml. The mixture was allowed to stand for two hours and then filtered in an atmosphere of dry nitrogen. The brown solid was reslurried in about 100 ml. of n-heptane and refiltered two times. The brown solid was finally reslurried in enough n-heptane to make the total volume of the mixture up to 250 ml. in a dropping funnel. V

" This slurry of brown solid in n-heptane was added to the Pyrex glass polymerization vessel containing 250 ml. of dry n-heptane which was blanketed with nitrogen and protected from moisture and oxygen. Purified dry ethylene was -bubbled into the liquid at the rate of 1,000 ml. per minute. The temperature rose from 26.3 to 34.0 C.'during the iirst 7 minutes with the absorption of about 3,200 Inl. of ethylene gas. Only a very little polymer was -noticed at this point with no more formed nor ethylene' absorbed during the next 10 minutes. At this point, 50 ml. of a 0.685 molar solution of dimethyl aluminum chloride in n-heptane was added to the polymerization vessel. The ethylene began to be completely absorbed 'J so'that the rate had to be increased to 1,500 ml. per

minute and the temperature rose from 33.3 to 55 C. in 3 minutes. This rate was continued for 24 minutes and then reduced to"1,000 ml. per minute as the temperature had risen to 83 C. After 7 more minutes with the temperature at 85.4 C., 250 ml. of dry n-heptane was added. About 10 minutes later there was some plugging of the ethylene inlet tube but the reaction was continued about an additional hour before 50 m1. of isopropanol was added to decompose the catalyst. The white solid polymer was removed by iiltration, washed with isopropanol and dried in vacuo at 68 C. The dry polymer weighed 92.7 grams, softened at 132 C., melted `at 135-142 C., and had an intrinsic viscosity of 2.80 cm.8102/ g., corresponding to a molecular weight of about 145,000.

- This experiment shows that dimethyl aluminum chloride, while an inactive catalyst component when reacted With TiCl4 alone,'is a highly eiective activating agent for the stored low activity brown precipitate formed by reacting TiCl., with ethyl aluminum compound.

Example III A slurry of ltered and washed'brown solid in dry n-heptane was prepared in the same manner and quantity as in the second experiment of Example II except that the initial reaction mixture stood 3 hours before ltering instead of 2. This slurry was placed in the polymerization vessel with n-heptane in the same manner as in Example II and ethylene bubbled therein. There was a added. The polymer was removed from the walls of the vessel and from the lstirrer and gas inlet tube. It was washed with isopropanol and dried in vacuo at 69 C. The total weight of polymer was 1.1 grams. The intrinsic viscosity of this polymer was 7.12 cm.3102/g.

as `a minimum value in tetralin at 125 C. since there little more initial reaction here with the temperature spontaneously rising to 61 C. with about 17,000 ml. of ethylene gas being absorbed before the reaction was complete and no more ethylene would react. After 15 minutes of no ethylene absorption, 50 ml. of a 0.121 molar solution of methyl aluminum dichloride in n-heptane was added to the polymerization vessel. Immediately all of the 1,000 ml. per minute of ethylene being introduced was absorbed with rapidpolymer formation. Another '50 ml. of a 0.121 molar solution of methyl aluminum dimethyl aluminum chloride with TiCl4 yields an extremely weak polymerization catalyst.

In a second experiment, 10 ml. of a 0.843 molar solution of` titanium tetrachloridein.n-heptane and l0 ml. of a 0.876 molar solutionof ethylaluminum compound (25%- triethyl aluminum-75%. diethyl aluminum `chlochloride was added after about 20 minutes. Ethylene absorption continued at least to 50% eiciency until the reaction was terminated because the gas inlet tube becarne plugged.` The catalyst was decomposed with isopropanol (50 ml.) and the solid polymer removed by filtration, washed with isopropanol and dried in vacuo at 68 C. The dry white polymer weighed 78.1 grams, softened at 133 C., melted at 154-187 C. and had an intrinsic viscosity of 5.04, correspondingto a molecular weight of about 336,000.

Example III demonstrates that methyl aluminum dichloride', which does.not form-an active catalyst with 'TiCl., alone, is an excellent activating agent forr alow activity Aprecipitate obtained by reacting TiCl4 with an Example IV In a first experiment 10 ml. of a 0.843 molar solution of titanium tetrachloride in n-heptane and 10 ml. of a 0.876 molar solution of ethyl aluminum compound (87% triethyl aluminum and 13% diethyl aluminum bromide) in n-heptane were added to 50V mi. of dry n-heptane at room temperature in an atmosphere of dry nitrogen. A brown precipita-te formed immediately. More n-heptane was immediately added to bring'the voiume of the mixture up to 100 ml. and it was vstoppered to exclude air. After standing 7 days at 1room temperature in 'Pyrex glass, this mixture was transferred to a Pyrex glass polymerizationfvessel with the exclusion of'air (nitrogen atmosphere). More dry n-heptane was added to make the yolume of the mixture upto 250 ml. Purified dry ethylene -was bubbled into the mixture with stirring. There was no temperature rise nor formation of polymer. The polymerization vessel was heated after 34 minutes until a'ternperature of 80* C. was reached during the next 40 minutes. Still no polymer was formed. The rate of ethylene gas bubbling into the mixture for a total of 1 hour and 18 minutes was 500 to 1,000 Inl. per minute. Isopropyl alcohol was added after this time to hydrolyze the catalyst but no polymer could be found.

This experiment shows that storage of a highly active polymerization catalyst for 7 days at room temperature completely deactivates the catalyst.

In a second experiment, 4 ml. of a 0.876 molar solution of triethyl aluminum in dry n-heptane and 4 ml. of a 0.843 molar solution of titanium tetrachloride in dry n-heptane were mixed in 50 ml. of heptane in a 100 ml. graduate, were made up to 100 rnl. with heptane, and this catalyst slurry was stored under nitrogen for l5 days at room temperature. After 15 'days this slurry was transferred to a 250 ml. separatoryfunnel, diluted to 250 ml. with dry n-heptane and transferred to a Pyrex glass reaction vessel under a nitrogen blanket. l Ethylene (Mathieson CP.) was bubbled into the reaction mixture. The ethylene absorption rate reached 350 nih/min.- in 32 minutes and the temperature increased from 28 to 45.8. C. in 47 minutes. 'i The absorption rate decreasedk to zero and the temperature dropped to 36.0 in 68 minutes. This slight activity could have produced a maximum of 9.8 grams of polyethylene as' calculated from the ethylene absorptionl` rates.^ At this point the. catalyst was inactive.

Twenty ml. of a 0.876 molar solution of ethyl aluminum dichloridey in dry heptane was diluted to 250 ml. with heptane in a separatory funnel and 50 ml. of this activator solution was added to the reaction mixture. The ethylene absorption rate increased to 250 Inh/min. and the temperature increased to 37.0 C. in 12v minutes. The additional 200 ml. of activator solution was added and the reaction mixtureV heated. The absorption rate increased to 1000 nil/min. in 1 48 minutes and the temperature increased to 77.2 C. The external heat source was removed when the temperature reached 67.8 C. after 114 minutes. The temperature was, maintained at, 55 -751 C. for an additional 68 minutes as the ethylene absorption rate decreased to 100 Inl/min. At this time the reaction mixture was cooled tov room` temperature and 100 ml. of isopropanol added to der activate and solubilize the catalyst.y The polymer slurry was filtered.- The dry Polymer. weighed 9.4.-'.64 grams of which atleast 84.8 grams was formedv after reactivation of the catalyst withl ethyl aluminum dChlQride as com-` pared to a maximum of 9.8 grams of polyethylene formed by the original catalyst. l'lffhis polymer had all intrinsic viscosity of 7.33 which is equivalent to a molecular weight of 570,000.

This experiment shows that ethyl aluminum, dichlQride largely deactivated by storage at room temperature for 1 5 days. t has been shown in Ex, vple llaf ethyl aluminum dichloride, when lreacted with TiCl4 alone, does not yield an active polymerization catalyst.

Example V Four ml. of a 0.843 molar solution of titanium tetrachloride in dry n-heptane and 4 ml. of a 0.876 molar solution o f triethyl aluminum (pure) in dry n-heptane were added to 100 ml. of dry-n-heptane in a 250 ml. sepaf ratory funnel and made up to 250 ml. Vwith heptane at room temperature in an atmosphere of nitrogen. A brown precipitate Vformed immediately upon addition of the aluminum alkyl to the titanium tetrachloride solution. This Vslurry was transferred to a Pyrex glass polymerization vessel under a nitrogen blanket, heated to 50 C. for 15 minutes and cooled to 29.2 C., and diluted with 500 Inl. of dry n-heptane. Ethylene (Mathieson C.P.)r was bubbled into the reaction mixture. The ethylene absorption rate increased to 250 ml./min. in 21 minutes and then decreased to zero in 78 minutes. The temperature reached a maximum of. 42.0"v C. in ,minutes and decreased to 38.4 C. in 78 minutes. The total ethylene absorption during this period indicated a maximum formation of 11.8 grams of polyethylene. The catalyst was inactive at this point.

One hundred ml. of an activator solution containing 6 ml. of a 0.876 molar solution of ethyl aluminum dichloride (86%) in 250 ml. of dry r1-heptane was added and the reaction temperature raised to 63.8 C. by external heating. The ethylene absorption rate increased to 300 ml./min. and the reaction was maintained at -60 C. for 20 minutes by adding 3 additional 5,0 ml. portions of the activator solution. Heat was applied to maintain the reaction in this temperature range for an ladditional 7 hours at which time the reaction ended as indicated -by a zero ethylene absorption rate. A total yield of 64.2 grams was obtained, of which at least 52.4 grams was formed after reactivation with ethyl aluminum dichloride original overheated catalyst. l The. polyethylene had an intrinsicviscosity of 6.78 equivalent to a molecular weight of 520,000 on the Harris scale.

Example VI In a rst experiment, 5 ml. of a 0.843 molar solution of titanium tetrachloride in n-heptane and 5l ml. of a 0.876 molar solution of ethyl aluminum compound (25% triethyl aluminum.-75% diethyl allnninum chloride) in n-heptane` were added to 10,0 ml. of, dry n-heptane in a dropping funnel in an atmosphere of dry nitrogen. A

rown precipitate formed immediately. More dry n-heptane was immediately addedv to make the total. volume or". the mixture up to 200 ml. After standingl hour, this mixture was added to the Pyrex glass polymerization vessel containing 250 ml. ofdry n-heptane protected from. air by an atmosphere of, dry nitrogen. lhernixturev was heated to 50 C. w-ith stirring and held' therey for about. 3 0. minutes. Ethylene (purified and dry) was then passed into the catalyst. mixture at 1,500. m1.` 'penminute tot: about 30. minutes, then at 11,000 mlL/min.. for 47. minutese and then at 5.00 ml`./min. for 20 minutes.` Pluggingv of the gas inlet tube occurredatthe end of4 the reaction but i ethylene absorption was already down. to 100. m1. per. minute. A total` o r` 450 additional. n-heptanefwas added during the polymerization. The catalystwas de.-

composed by adding` 50 ml. of., isopropanol. TheY white solidVV polymer Wasmemoved by filtration, washed with K 'f isopropanol,v and driedinvacuo at, 68 C. The dry polymer weighed; 79.0 grams, `vItl softened ati. 129 C, meltedV at 133i151 C., and. had an intrinsic. viscosityof 2.48- cxjnlzlg.,A corresponding; to a molecular weight of; about 121.000

tion of titanium tetrachloride in n-heptane and ml. of a 0.876 molar solution of ethyl aluminum compound (25%triethyl aluminum and 75% diethyl aluminum chloride) in n-heptane were added to 50 ml. of dry n-heptane. A brown precipitate immediately formed. More dry n-heptane was added to make the total volume of the mixture 100 ml. All operations were done in a dry nitrogen atmosphere. After standing 2 hours, the mixture was filtered and the brown solid was reslurried in dry n-heptane and refiltered. After another reslurrying and reliltering, the solid was slurried into a dropping funnel with a total of 250 ml. of dry n-heptane. This was transferred to the Pyrex glass polymerization vessel and stirred while purified dry ethylene was bubbled with the mixture. With 1,000 ml./min. rate of ethylene the ternperature of the mixture rose from 26.3 to a maximum of 28.9 C. in 10 minutes. The total absorption of ethylene was no more than 2,000 ml. No more ethylene absorption occurred at room temperature over the next 30 minutes nor at Ytemperatures up to 80 C. over the next 2 hours.

At this point the temperature was back down to 27 C. and 100 ml. of a n-heptane solution containing l0 ml. of a 0.876 molar solution of ethyl aluminum compound (the 25% triethyl aluminum- 75%diethyl aluminum chloride) was added. Immediately the rate of ethyl` ene addition had to be increased to 1,500 ml. per minute with complete absorption. The temperature rose from 27.0 to 75.0 C. in 24 minutes at which time the rate was reduced to 1,000 ml. per minute. After another 45 minutes at this rate the ethylene absorption was still 45% but the polymerization was voluntarily terminated. The catalyst was decomposed with isopropanol and the white solid polymer was removed by filtration, washed with isopropanol, and dried in vacuo at 69 C. The dry polymer weighed 67.7 grams. It softened at 158-182 C., melted only partially from l97-227 C., and had an intrinsic viscosity of 9.5, corresponding to a molecular weight of -about 840,000.

This experiment shows that the separated brown precipitate of an active catalyst is itself rather inactive but may be activated by the addition of alkyl aluminum compound.

Example VII The slurry of filtered brown solid was prepared and placed in the polymerization vessel in the same manner as in the second experiment of Example Vl except that it was allowed to stand only 1 hour before ltering. When pure dry ethylene was bubbled in, the temperature rose from 25.9 to 27.1 C. with only a little over 1,000 ml. of gaseous ethylene being absorbed. After 20 minutes of ethylene bubbling in at the rate of 1,000 mL/min. at room temperature and no absorption, dry hydrogen chloride gas was bubbled in for 2.5 minutes at 100 ml. per minute. No ethylene was absorbed due to this treatment.

After continuing the ethylene at 1000 mL/min. for another 16 minutes with no absorption, a solution (250 ml. total n-heptane used here) containing 10 ml. of a 0.876 molar solution of diethyl aluminum chloride was added.

Example VII shows that while HCl is ineffective as an activator of the separated catalyst precipitate, diethyl aluminum chloride may be used for this purpose.

Example VIII Ten ml. of a 0.843 molar solution of titanium tetrachloride in n-heptane and a 0.876 molar solution of ethyl aluminum compound (87% triethyl aluminum and 13% diethyl aluminum bromide) in n-heptane were added to 100 ml. of dry n-heptane in a dropping funnel protected with an atmosphere of dry nitrogen. A brown precipitate immediately formed. More n-heptane was immediately added to make the total volume of the mixture up to 250 ml. After 1 hour at room temperature this mixture was transferred to the Pyrex glass polymerization vessel protected at all times with an atmosphere of dry nitrogen. The stirred mixture was heated to 70 C. and held at this temperature for l5 minutes. It was cooled to 28.0 C. with an ice bath and then purified dry ethylene was introduced into the reaction mixture without cooling. The ethylene rate was 500 mL/min. initially and then 1000 ml./min. after l0 minutes (temperature at l0 minutes was 44.2 C.). The temperature was maintained between 60 and 65 C. by intermittent cooling.

After a total of 54 minutes of ethylene introduction, the temperature was declining and incremental addition of n-heptane solutions of the aluminum compound were made during the rest of the reaction. A total of 250 ml. of n-heptane solution containing 10 ml. of a 0.876 molar solution of ethyl aluminum compound (87% triethyl aluminum- 13% diethyl aluminum bromide) was made in 5 equal parts of 54, 66, 73, 90 and 130 minutes after lthe beginning of ethylene introduction. During this time the temperature was maintained at 60-65 C. and an additional 350 ml. of n-heptane was added to keep the slurry fluid. The reaction was terminated after 277 minutes at which time ethylene absorption was about ml./min. and temperature was 51.2 C. (No heating was applied throughout the time of ethylene addition.) The catalyst was decomposed by adding 100 ml. of isopropanol. The white solid polymer was removed by ltration, washed with isopropanol, and dried in vacuo at 70 C. The dry polymer weighed 163.5 grams. It softened at C., melted at 151230 C., and had an intrinsic viscosity of 7.47 cm.3102/g., corresponding to Y about 590,000.

This example shows the low activity of an overheated (15 minutes at 70 C.) catalyst mixture and its activation in accordance with the invention.

Example IX A catalyst mixture was prepared from the same stock solutions of titanium tetrachloride and ethyl aluminum compounds as in Example VIII, using the same volume of dry n-heptane, except that only half (5 ml. of a 0.843 molar solution of TiCl4 and 5 ml. of a 0.876 molar solution of alkyl aluminum) as much of the active ingredients being absorbed and the temperature rose 30C. in 8 minutes. The maximum temperature spontaneously achieved was 84 C. which occurred 4.7 hours after the addition of the aluminum. compound. Another 250 ml. of dry n-heptane was added during the reaction. Ethylene absorption remained at high elciency until there was so much polymer that ehannellingA took place with practically no stirring. The catalyst was decomposed with the addition of 50 ml. of isopropanol. The white solid polymer was removed by filtration, washed with isopropanol, and dried in vacuo at 68 C. The dry polymer weighed 240.6 grams. It softened at 129 C., melted at 238 C. and had an intrinsic viscosity of 8.34, corresponding to a molecular weight of about 690,000.

were employed. This mixture was stirred in the polymerization vessel for 15 minutes at 60 C. and cooled to room temperature (27 C.) before introducing ethylene. A solution (250 ml.) of n-heptane containing 5 ml. of a 0.876 molar solution of ethyl aluminum compound (87% triethyl aluminum-13% diethyl aluminum bromide) was added to the catalyst mixture just prior to starting to introduce ethylene. The rate of ethylene addition was 4 between 500 and 1500 ml./min. and the reaction ternperature maintained between 55 and 60 C. by intermittent cooling. No externa1 heating was applied. A total of 1,000 ml. of n-heptane was added during the reaction to keep the slurry fluid. The reaction was terminated after 4 hours and 32 minutes at whichy time ethylene absorption was down to 200 mL/min. and there was so much polymer present that stirring was very ineicient so that a temperature gradient of large magnitude existed in the polymerization vessel. The catalyst was decomposed by the addition of 100 ml. of isoprotemperature (32-26 C.) ifor 52 minutes.

yim

Y pjanol. ''he white solid polymer `was remoueid J.byfiiltration, washed with 'isopropanohanddried .in vacuo `at 70 C. The dry polymer weighed.23 6.`5 grams. It softjened at I183 C.,'partially melted at ,227 'to .f2'50I-f 4C., jand had anintrinsic viscosity of 8.07 'cm'IOZ/grcorr'espending to amolecular weightof ab outl670,00,0.

The jcatalyst deactivated by overheating l(15 i n inutes at 60 C.) 4was reactivatedby .the addition 'of alkyl aluvmilum.compound vprior to the polymerization reaction.

`Example X A catalyst'solution was preparedjnthefsarne manner as yinlxampleIX using Symlofa 0.1843 molar-solution Vof TiCLiV and ml. -of La 0.876 -mol-arrsolution Y.of -ethyl aluminum 'compound (8,7% triethyl aluminum-71,3% diethyl aluminum bromide). The 250 m1. mixture was `'stirred Yand'heated to 70 `C.in the polymerization vessel `and -held at this temperaturefor 15 minutes. It wasthen cooled in anice bath to32 C. At that time -a 2.50 m1,

.Ilvheptane solution Vcontaining ,-5 aml. .of a 0.876 molar solution of ethyl .aluminum compound .(87% triethylalu- 4:nimm-13% diethylaluminum bromide) was added to .the catalyst mixture. 1T his was allowed `to stir at room During this ,time the-precipitate turned froma :redbrown occulent .to a more dense black precipitate. Purified dry ethylene was then introduced at 500-1000 ml. /min. The rtemperature rose spontaneously .to only 35 C. Vafter 19 minutes and the maximum-ethylene @absorption was 500 nih/min.

Aj I- Ieat -was rappliedto keepthe temperature at about 50 C.

Ima nrsfexpaimem? lojm't- Qf abats metaframe@ y .of titanium tetrachloride in fnlheptane and of a 0.876 molar solution of .ethyl aluminum .compound V.(87%

triethylaluminum-l'q diethylaluminum bromide) n-heptan'ewere added 'to y1.00 ml.`of dryn-heptan'e. vA

brown'p'recipita'te l-iormed immediately. lfifi/lore '.nheptane was `added immediately vto make lthe total yoluiiie Vof the mixture up to '100 ml. using an atmosphere'of dry nitrogen at all times. `It w'asstored at room temperature ,for

2 days (51 hours) and then 'made lup .to 250 inl. -with polymerization .tivas lattemptedfno yetliylene'vt/as absorbed .and no I.polymer Vwas Qfor'm'ed, -showing ythat the .catalyst Vhad .become 'completely d'eactivated during storage. The fstirrfed niixture 'wasiheatedfrom room temperature lgradutinuousiiitrduction of'etn'ylene at SOO-1,000 Inl/min. ln a thirdlexperiment, `the catalyst V"prepared-in .the

samemanner as in the second experiment was again `found to have `noactivity ;with ethylene at-room temperature 2 (28 .8 .C .'forf15 minutes of introducing `the gas at l500 mL/min. ,Fl1owing,this, 25,0 ml. of n-heptane's'olution. 'containinglO nil. of a 0.876 molar solution of ethyl alumiv num compound .(87% Vtriethyl aluminum-13% diethyl Y'.iiur'n.intim bromide) was added in soimipsrtionsjat 15 .2-1, 27, 41 and 55niinu'tes afterstarting ethylene introduction. This catalyst mixture became active enough Yto .formpoly-mer slowlyjbut heat -was yapplied to raise .the

temperature from 35 1to 50 C. to help speed, up the V'absorption of ethylene, After ,a total Yof v2Vhours and 2 6 n-heptane and transferred to the Pyrex glass polymerzationvessel. Purified .dry ethylene was introduced into thestirred mixture at a rate of 1,000 ml. per rminutefor a total of 1 hour. The temperature rose from 26.0 to

65.76 C. in 18 minutes. Cooling `was applied to 4keep the'temperaturebetween 60 and 70 C. Therewas practically no `absorption of ethylene and the temperature had 4dropped rto 49 C. when the kcatalystwas decomposed by the addition of 50 ml.. of isopropanol. The white solid polymer was removed'by'ltratiomjwashed with isopropan'ol, and dried in yacuo at 70 C. The dry polymer weighed 36.0 grams. `If softened `2't*c fl": `5 C., partially meltedat 205 to 250 C., and had an'intrinsic viscosity 0f`3.39 cm102/g., corr'esponding'to'a molecular Lweight k0f y about 190,000.

This experiment shows the :low'factivityof a catalyst y,

stored'for 2 days.

In a second 'expermejnn the catalyst was prepared in the same manner/and with the same reagents and quantities las in the-rst experiment except thatithe mixture was `storedunder dry nitrogen for 7 days .instead of 2 days p before introducing ethylene for polymerization. yWhen -mer weighed 75L4 grams.

minutes the .ethylene ow was stopped andthe catalyst was decomposed by'addingSOml. of isopropanol. The

polymer was, recovered by ,iiltratiom ffwashed with iso'- propanol, anddriedfin vacuo at :70 C. The drypolymer weighed 10.2 grams. It softened :at 135 -C. and partially melted at 151 -240+ C. Y

This `experiment shows some reactivation of the catalyst by addition of alkyl aluminum compound to the total deactivated catalyst composite.

In a fourth experiment, l0 m1. of a 0.843 molar solution of titanium tetrachloride in n-heptane and l0 ml. of ,a `0.876 molar solution of ethyl aluminum compound Y (87% triethyl aluminum-943% diethyl aluminum brotnide) Vin'nfheptanewereadded to.50 ml. of dry n-heptane. A 'brown'precipitate formed immediately. More dry n- 35 heptane was immediately added to make the total volumeof the mixture ml. All operations were in an Yatmosplwre of dry nitrogen.V This mixture 'was vstored "for 7 days andtheh filtered in an atmosphere of dry `nitrogen. The brown lsolid 'was reslurried in dry n -hepytane and reiiltered twice. The brown solid was then reslurriedin l250 ml. of dry n-heptane and lplaced in the ',Pylje'x polymerization vessel containing 250 m1. of

n-heptanein an atmosphere of'dry nitrogen. P uriied dry, ethylenevintroduced into the ystirred mixture with no absorptionf'norpolymerformation even after heating from '2652 C. w'ith mlz/min. of lethylene'ilow for 30 minutes. f

After menage-26 C., 'so un. of fri-heptane solution ';ontaiiiing a A0.876 vmolar solution of ethyl aluminum compound (87% triethyl aluminum-13% diethyl aluminum bromide) was added. Ethylene absorption began rapidly to inrease to .90% of the 1000. mL/min. flow n rate andthe :temperature of therstirre'd mixture roseto 60 C. in '18 minutes. The temperature was maintained between '58 land l64" C. by intermittent cooling with a waterbath.v Thereaction was terminated as the vethylene absorption fell to about 100 mL/min. and the .temperature Ydropped to 46 C. after 3 hours, 20 minutes. lThe catalyst was decomposed'by adding 50 ml. of isopropanol. Thepolyrner was removedjby filtration, washed with iso- 'pr'opanoh and dried "in vacuo lat 70 C. The dry "poly- It softened at 166+ C., `par 'tially melted at y200 to240+ C., and had an intrinsic lviseosity of 9.04 cmlOfg;a corresponding to a 4molecu- 'lar Weight 'of 4about 780g000.

This experiment shows that yaddition ofthe activating alkyl aluminum compound tothe separated catalystprecipita'te is more eiective than addition to the total original catalyst composite. Example 'XII Ten inl. of 'a 0.843 molar solution oftitanium tetra-Y y chloride inn-heptane Aand 10 ml.y of a'0.876 molan-solution 'of Vethyl aluminum compound (87% ,triethyl alumi-,j

num-413% diethyl aluminum bromide) in n-heptane were added to 50 ml. of dry n-heptane." A brown pre? y i `cpitate formed immediately. More dry n-heptane was immediately added to make the total volume of the mixture 100 ml. All operations were in an atmosphere of dry nitrogen. After standing for 1 hour, the mixture was ltered in an `atmosphere of dry nitrogen. The brown solid was reslurried in dry n-heptane and refiltered twice. The brown solid was then reslurried in 100 ml. of dry n-heptane and allowed to stand for 7 days (during storage the stopper became loose and some air entered, enough to decolorize yfrom brown to white about 10% of the brown solid in the mixture). This did not affect most of the brown solid nor its activity to any extent as seen below.

After the 7 days of storage, the mixture was made up to 250 ml. with dry n-heptane and transferred to the Pyrex glass polymerization vessel containing 250 ml. of dry n-heptane protected with an atmosphere of dry nitrogen. Purified dry ethylene introduced into the-stirred mixture failed to react at 27 C. for a period of 30 minutes. This shows the inactivity of the brown solid without the alkyl aluminum compound in the mixture as expected from the experiments above.

A 250 ml. n-heptane solution containing 10 ml. of a V0.876 molar solution of ethyl aluminum compound (87% triethyl aluminum- 13% diethyl aluminum bromide) was then added in 50 m1. portions, one at this time and the others 36, 68, 91 and 100 minutes later. Ethylene absorption was rapid after adding the aluminum compound and intermittent cooling was applied to keep the temperature between 55 and 60 C. Ethylene flow rate was maintained at 500 to 1,000 ml. per minute for 3 hours and 58 minutes after the rst portion of the aluminum compound was added. About midway through the polymerization, 250 ml. of dry n-heptane was added to help keep the slurry uid. The polymerization was voluntarily terminated even though there was sti1l300 ml. of ethylene being absorbed per minute and the temperature was being sustained at 51 C. by heat of reaction. The catalyst was decomposed by adding 50 ml. of isopropanol. The white solid polymer was removed by filtration, washed with isopropanol, and dried in .vacuo at 70 C. The dry polymer weighed 92.3 grams. It softened at 140 C., partially melted at l69-240+ C., and had an intrinsic viscosity of 9.80 cm.3l02/g., corresponding to a molecular weight of about 870,000.

This example demonstrates that the separated precipitate from the original catalyst composite is stable for long periods of time and may thereafter be converted into an active catalyst in accordance with the present invention.

Example XIII In a first experiment, 11.1 ml. of a 10% by weight solution of AlEtClz was added to 50 ml. of dry n-heptane in a 250 ml. separatory funnel. Then ml. of a 0.843 molar solution of TiCl4 in heptane were added. The mixture was made up to 250 ml. with dry n-heptane and placed in a 2-liter glass reactor vessel. The mixture was a light yellow clear solution. Heat was applied to bring the mixture to 50 C. and it was maintained at 50 C. for 15 minutes. No change in the reaction mixture was observed. The mixture was cooled to 27.0 C. and ethylene was bubbled into the reactor. No ethylene absorption was noted. A few small droplets of yellow oil deposited on the glass surface of the reactor. After 30 minutes heat was applied and the temperature increased to 81.2 C. for 30 minutes. A few small droplets of yellow oil deposited on the glass surface of the reactor. No ethylene absorption was noted. The mixture was cooled to 40.2 C. and reheated to 83.0 C. No ethylene absorption was observed. The mixture was cooled to 42.5 C. and 50 ml. of isopropanol were added. Thesolution became clear and white. The few small yellowdroplets disappeared. `A large excess of isopropanol was added, but no evidence of polymer was noted.

tactive polymerization catalyst.

bubbled into the reactor.

This experiment again shows that ethyl aluminum dichloride does not react with TiCl4 alone to form an In a second experiment, 1.5 grams of Naas a sta- 'bilized 50% sodium dispersion. in heptane containing sodium particles of l to 30 diameter averaging a particlesize of 15, was placed in 250 ml. of n-heptane in a separatory funnel in a nitrogen dry box. Similarly 20 ml. of a 0.843 molar solution of TiCl4 in n-heptane and 20 ml. of aO.876 molar solution of EtAlCl2 were that temperature for 15 minutes with stirring. The light gray slurry darkened to a medium brown color. The mixture was cooled to 30 C. and then ethylene was No change in temperature or absorption of ethylene was observed for 15 minutes. Then 50 ml. of the activator solution of ethyl aluminum `dichloride was added. No temperature change or ethylene absorption was observed. The remaining 200 ml. of activator solution was added with no evidence of polymerization over a period of 3 minutes. The reaction mixture was then heated. At 56.2 C. ethylene ab` sorption was noted as 250 ml./min. and polymer particles began to appear in the slurry. The mixture was heated to 64.0 C. in 9 minutes and the ethylene absorption rate increased to 750 mL/min. The external Yheat source was removed. The temperature increased spontaneously to 77.2 C. and the ethylene absorption rate increased to 1250 ml./min. The ethylene feed stream was then diluted with 250 ml./min. of NZ and the ethylene absorption rate was maintained at 1000 mL/min. for 30 minutes. The temperature was main- 'tained between 60-70 C. by cooling with tap water. `The ethylene absorption rate gradually decreased during the next 3 hours and near the end of the reaction heat was applied to maintain the temperature between 60- '70 C. The reaction mixture was cooled to 30 C. and

ml. of isopropanol was added. The slurry turned white. The polymer was filtered and dried in vacuo. The solid polymer weighed 104.0 grams and 4.1 grams of soluble polymer was recovered from the filtrate.

tetrachloride and trialkyl aluminum or dialkyl aluminum halide is separated by filtration before it is treated with the alkyl aluminum compound for improved catalytic activity.

The invention is not limited to the specific figures of the foregoing examples. The relative proportions of the materials used and the reaction conditions may be varied within the limits indicated in the specification to obtain products of varying characteristics.

What is claimed is:

- l. The method of preparing catalysts for olefin polymerization which comprises mixing a solution of an alkyl aluminum compound selected from the group consisting of triethyl aluminum and diethyl aluminum halide with a solution of titanium tetrachloride to form a slurry of a precipitate containing a reduced modification of titanium tetrachloride and mixing said precipitate, whose This is particularly Vtrue where the brown solid reaction product of titanium having a relatively low reducing activity, differing from said alkyl aluminum compound previously utilized and selected from the group consisting of ethyl aluminum dihalides, methyl aluminum dihalides, and dimethyl aluminum halides, to form a polymerization catalyst of increased activity.

2. The method of preparing catalysts for olefin polymerization which comprises mixing a solution of an alkyl aluminum compound selected from the group consisting of triethyl aluminum and diethyl aluminum halide with a solution of titanium tetrachloride to form a slurry of a precipitate containing a reduced modification of titanium tetrachloride and mixing said precipitate, whose polymerization activity is reduced by heating prior to contact with oleins, with an alkyl aluminum compound having a relatively low reducing activity, diiering from said alkyl aluminum compound previously utilized and selected from the group consisting of ethyl aluminum dihalides, methyl aluminum dihalides, and dimethyl aluminum halides, to form a polymerization catalyst of increased activity.

3. The method of preparing catalysts for olefin polymerization which comprises mixing a solution of an alkyl aluminum compound selected from the group consisting of triethyl aluminum and diethyl aluminum halide with ducing activity, differing from said alkyl aluminum comv pound previously utilized and selected from the group consisting of ethyl aluminum dihalides, methyl aluminum dihalides, and dimethyl aluminum halides, to form a polymerization catalyst of increased activity.

References Cited in the le of this patent UNITED STATES PATENTS 2,388,178 Peterson Oct. 30, 1945 2,396,920 Larson Mar. 19, 1946 2,439,765 Walker Apr. 13, 1948 2,600,654 Jacobson June 17, 1952 2,824,089 Peters et al. Feb. 18, 1958 2,827,446 Breslow Mar. 18, 1958 FOREIGN PATENTS 789,781 Great Britain Apr. 17, 1955 526,101 Italy May 14, 1955 534,792 Belgium Ian. 31,

Notice of Adverse Decision in rInterference In Interference No. 93,636 involving Patent No. 2,943,063, L. T. Eby, C. W. Seelbach, D. L. Cottle and R. M. Thomas, CATALYSTS FOR POLYMERIZATION OF OLEFINS, nal judgment adverse to the patentees was rendered Dee. 6, 1965, as to claims 1, 2 and 3.

[Ooz'al Gazette May 17, 1.966.] 

1. THE METHOD OF PREPARING CATALYSTS FOR OLEFIN POLYMERIZATION WHICH COMPRISES MIXING A SOLUTION OF AN ALKYL ALUMINUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF TRIETHYL ALUMINUM AND DIETHYL ALUMINUM HALIDE WITH A SOLUTION OF TITANIUM TETRACHLORIDE TO FORM A SLURRY OF A PRECIPITATE CONTAINING A REDUCED MODIFICATION OF TITANIUM TETRACHLORIDE AND MIXING SAID PRECIPITATE, WHOSE POLYMERIZATION ACTIVITY IS REDUCED BY STORAGE PRIOR TO CONTACT WITH OLEFINS, WITH AN ALKYL ALUMINUM COMPOUND HAVING A RELATIVELY LOW REDUCING ACTIVITY, DIFFERING FROM SAID ALKYL ALUMINUM COMPOUND PREVIOUSLY UTILIZED AND SELECTED FROM THE GROUP CONSISTING OF ETHYL ALUMINUM DIHALIDES, METHYL ALUMINUM DIHALIDES, AND DIMETHYL ALUMINUM HALIDES, TO FORM A POLYMERIZATION CATALYST OF INCREASED ACTIVITY. 